STABILIZING SELECTION FOR LOWER PHENOTYPE VARIABILITY OF RABBITS
Keywords:
stabilizing selection, number of liveborn kits, milk yield, determination coefficient, vitalityAbstract
Stabilizing selection for lower variability of liveborn kits in a litter resulted in higher vitality and significantly (P < 0.05) higher mean number of weaned kits at 35 days of age. In the group of kits from selected mothers with higher variability per litter and coefficient of variation > 11 %, the mortality to weaning (35 days) and post-weaning (42 days) was 27.27 %. In the group from mothers with lower variability between litters and coefficient of variation < 11 %, the mortality within this period was zero. Females with lower variability of liveborn kits per litter and their kits at the 42nd day of age showed lower level of C-reactive protein (CRP) in blood plasma compared to the second group. Strong negative correlation (r = -0.795) was confirmed between the coefficient of variation of liveborn kits and the number of weaned kits with coefficient of determination r2 = 0.633. In practice it means that higher balance or lower variability of the number of liveborn kits between the individual litters has positive influence on the number of weaned kits and this parameter was influenced on up to 63.3 %, while the rest of the influence (36.7 %) was entirely random. Strong negative correlation (r = -0.94) was noted also between the markers of milk yield in females up to the 21st day and the variation coefficient of liveborn kits. The determination coefficient in this case was r2 = 0.884. These data suggest that higher stability of liveborn kits numbers between litters has a positive effect on the number of weaned kits of rabbits and also that targeted selection for lower levels of C-reactive protein in blood plasma can help to improve effective production through more effectively innate immunity against pathogens and therefore lower mortality of growing rabbits.
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